Universal interlock



July 21, 1953 Filed Dec. 7, 1949 R- L. STRATTON UNIVERSAL INTERLOCK 4Sheets-Sheet l INVENTOR.

ROBERT L STRA'TTON A TTOE/VEYS July 21, 1953 R. L. STRATTON UNIVERSALINTERLOCK Filed D80. 7, 1949 4 Sheets-Sheet 2 INVENTOR.

ROBERT l STRATTON ATTORNEYS R. L. STRATTON UNIVERSAL INTERLOCK July 21,1953 4 Sheets-Sheet 5 Filed Dec. 7, 1949 FIG. 4.

INVENTOR.

Roiimi ybzaifmz Gila M21294 R. L. STRATTON UNIVERSAL INTERLOCK July 21,1953 4 Sheet-Sheet 4 Filed Dec. 7, 1949 INVENTOR.

ROBERT l STRATTON dmxmk V 1%;,

ATTORNEYS.

Patented July 21, 1953 UNITED STATES PATENT OFFICE UNIVERSAL INTERLOCKRobert L. Stratton, Folcroft, Pa., assignor to I-T-E Circuit BreakerCompany, Philadelphia, Pa., a corporation of Pennsylvania ApplicationDecember 7, 1949, SerialNo. 131,524

My present invention relates to circuit breakers and more particularlyto interlocking devices for use in connection therewith, the saidinterlocking device being so arranged that the operation of one circuitbreaker will effect or control the operation of another circuitbreakerfA specific object of my invention is the provision of an interlockingdevice which may be used in any designed grouping of circuit breakersoperating in respect to horizontally adjacent or vertically adjacentcircuitbreakers and even with respect to circuit breakers which arediagonally arranged with respect to each other.

Another object of my inventionis the provision of a novel interlockingdevice which may be used in connection with stationary mounted circuitbreakers or truck mounted removable circuit breakers.

Another object of my invention is the arrangement of, an interlockingdevice so that the interlocking-element positively blocks the movablecontact arm 'in the open position and prevents it from closing thecircuit breaker regardless of any tampering with the circuit breaker orits accessories.

My invention contemplates the arrangement of a push rod adjacent amovable contact arm of a circuit breaker, the push rod being sopositioned that when the circuit breaker is closed, the push rod ismoved longitudinally. A dog leg or bell crank lever, a link and anadditional dog leg or bell crank lever are connected to another push rodso that when the first push rod is moved longitudinally by the closingof its associated circuit breaker, the other push rod is movedlongitudinally in the opposite direction to block the contact arm of theother circuit breaker.

The latch and other mechanism which thus holds the first circuit breakerclosed also holds the second push rod in position so that the secondcircuit breaker cannot be closed.

The foregoing and many other objects of my invention will becomeapparent in the following description and drawings in which:

Figure 1 is a schematic side view showing the interlock of my inventionapplied to vertically adjacent circuit breakers.

Figure 2 is an enlarged side view of the push rod interlock constructionof Figure 1.

Figure 3 is a rear view of the push rod interlock construction ofFigures 1 and 2.

Figure 4 is a schematic top view showing the utilization of my novelinterlock construction as applied to circuit breakers arranged side byside.

Figure 5 is a rear view of the horizontal interlock construction ofFigure 4.

4 Claims. (Cl. 200-50) Figure 6 is a detailed view showing theapplication of my novel interlock construction as applied to a draw-outtype of circuit breaker.

Referring first to Figure 1, the circuit breakers Iii and I: are mountedon their vertically adjacent panels I2 and I3. Each circuit breaker is"provided with its movable contact arm 14', I5 rotatably mounted on theirrespective cross shafts i6, i1 and being operated in any suitable mannereither'by the operating handle 18, is through the operating mechanism26, 2|, the solenoid closing coil 22, 23 or the overload trip units 2 3,25.

Push rod 30 is slidably mounted in opening '3! i in panel I2 and isslidably carried by the, additional bracket 32 secured in any suitablemanner to the rear of panel I 2. The dog leg or bell crank lever 34 issecured in any suitable manner on the pivot 35 at the downwardlydirected extension 36 of bracket 32 so that it may rotate with respectthereto. u I

Reference should also be made to Figures 2 and 3 since Figure 2 showsthe construction of Figure 1 greatly enlarged with a slight modificationhereinafter referred to, and Figure 3 shows the rear view of the unitsof Figures 1 and 2.

End 40 of the push rodeo bears against leg 42" of the bell crank lever34. The opposite leg 43 of the bell crank lever 34 is pivotallyconnected at 44 to the link 45. The lower end of link 45 is pivotallyconnected at pin 58 to the leg ii of dog leg or bell crank lever 48which is pivotally mounted at 49 on the upwardly directed extension 50of the bracket 5| secured to' panel 13 and which slidably supports thepush rod 55.

End 5 6 on the rear end of the push rod extends behind the leg 6!] ofthe bell crank lever Hand is engaged thereby.

It will now be seen that when the movable contact arm M of the circuitbreaker It is rotated to the closed position and therefore is rotated tothe right and clockwise, it pushes the push rod 33 to the right, therebypushing the end it of the push rod 30 to the right and rotating the bellcrank lever 34 in a clockwise direction.

This in turn raises the pivot 44 of link 45 drawing up link 45 and alsorotating bell crank lever 48 in a clockwise direction driving the leg 60thereof to the left. The rotation of the bell crank lever 48 in aclockwise direction therefore drives the push rod 55 to the left intoblocking relation with the contact arm l5. Thus the contact arm cannotbe moved to closed position since, in order to do so, it must move thepush rod 55 to the right, but the push rod 55 is held in position by thelinkage connection to push rod 39 which in turn is held against movementto the left by the closed position of contact arm 14.

In other words, the push rods 30 and 55 are arranged so that one willmove to the left while the other moves to the right and if the closingof one circuit breaker which requires a movement to the right of thepush rod is blocked by reason of the fact that the other push rod cannotmove to the left owing to the closing of the second circuit breaker,then the circuit breakers are completely interlocked and one cannotclose unless the other is opened.

Thus as seen in Figures 1, 2 and 3, the lower circuit breaker ll cannotclose owing to the fact that the other circuit breaker IE3 is open.Nothing interferes, however, with the opening of the other circuitbreaker ID.

When the contact arm M of the upper circuit breaker ill has moved to theleft to open position, then the push rod 30 is free to move to the leftand will do so when the lower contact arm is moved to closed position,moving the push rod 55 to the right. This operation will reverse thecondition shown in Figure 1 and Figure 2 so that push rod will be movedto the left to hold the contact arm l4 locked in the open position.

There is thus no way by which, when the circuit breakers are connectedby this kind of interlock that one circuit breaker can be closed whilethe other remains closed. While they are thus connected for alternateoperation, an operator who may desire to make some adjustments withrespect to one of the circuit breakers can be certain that as long asthe other circuit breaker is closed, the circuit breaker on which he isworking will remain open.

In order to ensure this, the operator may pass a hasp of a padlockthrough opening it or H on the respective brackets 5| and 32 to blockthe movement of the dog legs 48 or 34 with the associated circuitbreaker in the open position and with the push rod moved to a positionwhere the opening 10 or H as the case may be is on the right side of thedog legs 34 or 48.

In this case, the push rod 30 or as the case may be will be locked inthe lock open position with the particular circuit breaker. Eithercircuit breaker, as will be obvious, may be tripped to the open positionwhile the other circuit breaker is open but the arrangement is such thatboth circuit breakers cannot be closed at the same time.

In Figure l I have shown my interlock mechanism applied to two identicalcircuit breakers. In Figure 2, I have shown two different types ofcircuit breakers thus interlocked with the contact arm Me of circuitbreaker 10a being. of a different construction from the contact arm [5of circuit breaker II.

It will be obvious that the circuit breakers or switch gear thusinterlocked need not have identical construction but need only have someangular or translatory movement between the closed and the open positionto make my novel interlock operable.

It will also be obvious that circuit breakers may be successivelyinterlocked or one circuit breaker may be interlocked with a number ofothers, either horizontally or vertically or diagonally adjacent so thatwhen any one of a number of circuit breakers is closed, the particularcircuit breaker which is interlocked with all of them must necessarilyremain open.

In Figures 4 and 5 I have shown the arrangement of my invention foroperation in connection with horizontally adjacent circuit breakers andalso where circuit breakers are successively interlocked. Thus thecircuit breaker H6 may have all of the constructional attributes of thecircuit breaker ll of Figure 1 and the circuit breaker Ill may becorrespondingly similar to the circuit breaker l l of Figure 1.

Push rod 30 passing through the panel 12 will be operated in the mannerpreviously described and will operate the angle member 34 in acounterclockwise direction about its pivot 35. This will in turn throughlink 45 operate the angle member 48' in a counterclockwise direction todrive the push rod 55 inwardly.

The operation here is identical with that previously described inconnection with Figures 1 to 3, except that the operation is performedin a horizontal direction.

Here the circuit breaker H0 is shown closed and circuit breaker Ill hasits push rod 55 extended towards the front to lock the circuit breakerH! open. The circuit breaker Ill also has the additional push rod I35operating from another of the poles of the movable contact arm of thecircuit breaker Ill and through the dog leg I34 and connecting link [45to an adjacent circuit breaker.

Thus the closing of the adjacent circuit breaker on the'right side alsolooks circuit breaker Hi open and the opening of circuit breaker illwill leave the circuit breaker on the right side, not shown, in positionto open or close freely as is the circuit breaker I 19 on the left side.

Similarly push rod !-55 of circuit breaker Iii) is pushed towards therear by the closing of circuit breaker l i6 and operates through thehorizontal bracket I32 and the dog leg I48 and connecting link i l-5a tolock the adjacent circuit breaker on the left side open.

By this means not only may a horizontal interlock be achieved, but alsoa multiple interlock in series may be achieved. It is also obvious thatthe link may extend vertically to a vertically adjacent circuit breakerand link 145a may extend laterally to a horizontally adjacent circuitbreaker and that other multiple arrangements may be provided.

In Figure 6, I have shown the application of my invention to a draw-cuttype of circuit breaker having a stationary panel 222 and a movabletruck mounted panel 2l2a carrying a back connection stud 359 and a backdisconnect contact 39! engaging the stationary back disconnect contact362 on the stationary panel 212. The push rod 235 is slidably mounted inopening 231 in stationary panel 2 12 extending out past the bracket 232which carries the dog le 234 pivotally mounted at 235 downwardlydirected extension 236 of bracket 232.

When the circuit breaker 2|!) on the truck mounted panel 2I2a is rackedinto position, the push rod 238 operates in exactly the mannerpreviously described in connection with push rod 30 of Figure 1.

Push rod 236 is appropriately extended for this 5. coupling 3 i.'.={-which" extends the pu'shrod through opening'zfiic in panel 2i2a so thatthe extension 235m of push rod 230 may operate in connection With themoving contact arm of the circuit breakerZHl. j g

Thus when all of the circuit breakers are racked in position, theinterlock operates through the connecting link 2 l5'in exactly themanner previously described in connection with Figure'jl.

'When the circuit breaker Zill is opened the ope'ratorbypassing thehasp' of'a padlock through opening 21! of bracket 232may lock the pushrod 236 in a circuit blocking or circuit opening position for circuitbreaker 210. When the circuit breaker 2H is thereafter racked out, thepadlock in opening 21! will ensure that the circuit breaker 21!! cannotbe racked in in closed position,

Assuming that after various operations on the circuit breaker 2H1 in theupper compartment in Figure 6, it happens to remain in closed positionbefore it is racked in, then as it is racked in, the push rod 239 willengage the moving contact arm thereof before the movable disconnectcontact 3%! engages the stationary disconnect contact 302 and preventthe further racking in of the circuit breaker unless the circuit breakeris tripped open. By this means, therefore, the operator by placing apadlock through opening which the circuit breaker has been racked out,

operated by the closing of its associated movable armto rotate itsassociated bell crank about its pivotand moving through saidconnectingrod the other of said bell cranks and the push rod of theother of said circuit breakers to the position corresponding to thecircuit open position of the movable 'arm of said other circuit breaker.

-In combination, a first circuit breaker, a second circuit breaker, eachof said circuit breakers having a fixed contact and a movable armcarrying a movable contact engaging and disengaging with its associatedfixed contact a panel, a movable disconnect contact, a stationarydisconnect contact mounted on said panel and engageable with itsassociated movable disconnect contact when the circuit breaker is rackedinto position therefor, a push rod slidably mounted on said panel, a

will be assured that said circuit breaker may not be racked into saidcompartment in a closed position and that said circuit breaker afterbeing racked in may not be closed until he has removed the padlock fromthe opening 2'.

I claim: I

1, In combination, a first circuit breaker, a second circuit breaker,each of said circuit breakers having a fixed contact and a movable armcarrying a movable contact engaging and disengaging with its associatedfixed contact, a panel, a movable disconnect contact, a stationarydisconnect contact mounted on said panel and engageable with itsassociated movable disconnect contact when the circuit breaker is rackedinto position therefor, a push rod slidably mounted on said panel, abell crank, one arm of said bell crank being engageable by one end ofits associated push rod, a connecting link connecting the other arm ofthe bell crank for adjacent circuit breakers, a bracket secured to saidpanel, said push rod extending through said bracket, said bell crankbeing pivotally mounted on said bracket for movement about its pivotwhen operated by its associated push rod, means for supporting saidbracket on its associated panel, a coaxial rod for said push red, oneend of said auxiliary rod engaging said push rod and the other end beingengageable with the movable arm of the associated circuit breaker, thepush rod, its auxiliary rod, and its bell crank having one position forthe circuit closed position of its associated circuit breaker and havinga second position for the circuit open position of its associatedcircuit breaker, means for locking the bell crank in the positioncorresponding to the circuit open position of the circuit breaker, theend of the auxiliary rod engaging its associated push rod when it is inthe position corresponding to the closed position of its associatedcircuit breaker before the associated movable disconnect contact engagesthe associated fixed disconnect contact to prevent further racking ofsaid circuit breaker while said circuit breaker is closed, the push rodor" one of said circuit breakers being bell crank, one arm of said bellcrank being engageable by one end of its associated push rod, aconnecting link connecting the other arm of the bell crank for theadjacent circuit breakers, a coaxial auxiliary rod of said push rod, oneend of said auxiliary rod engaging said push rod and the other end beingengageable with the movable arm of the associated circuit breaker, thepush rod, its auxiliary rod, and its bell crank having one position forthe circuit closed position of its associated circuit breaker and havinga second position for the circuit open position of its associatedcircuit breaker, the end of the auxiliary rod engaging its associatedpush rod when it is in the position corresponding to the closed positionof said first circuit breaker before the associated movable disconnectcontact engages th associated fixed disconnect contact to preventfurther racking of said circuit breaker while said circuit breaker isclosed.

3. In combination, a first circuit breaker, a second circuit breaker,each of said circuit breakers having a fixed contact and a movable armcarrying'a movable contact engaging and disengaging with its associatedfixed contact, a panel,

a movable disconnect, a stationary disconnect mounted on said panel andengageable with its associated movable disconnect when the circuitbreaker is racked into position therefor, a push rod slidably mounted onsaid panel, a bell crank, one extension of said bell crank beingengageable by one end of its associated push rod, a connecting linkconnecting the other projection of the bell crank for adjacent circuitbreakers, a bracket secured to said panel, said push rod extendingthrough said bracket, said bell crank being pivotally mounted in saidbracket for movement about its pivot when operated by its associatedpush rod, means for pivotally supporting said bracket on its associatedpanel for permitting rotation of said bracket and its associated bellcrank through different angular distances, means for locking the bellcrank in the position corresponding to the circuit open position of thecircuit breaker, the push rod of each of said circuit breakers beingoperated by the closing of its associated movable arm to rotate itsassociated bell crank about its pivot and moving through said connectingrod the other of said bell cranks and the push rod of the other of saidcircuit breakers to the position corresponding to the circuit openposition of th movable arm of said other circuit breaker.

4. In combination, a first circuit breaker, a second circuit breaker,each of said circuit breakers having a fixed contact and a movable armcarrying a movable contact for engaging and disengaging its associatedfixed contact, a push rod and bell crank for each circuit breaker, arotat- ROBERT L. is'I'RATtI'ON.

References Cited in the file of this patent UNITED STATES PATENTS NumberName Date Dewson Jan..31, 905 Scott Dec. 18, 1917 Andersen Mar. 10, 1931Forstrom .May 18, 1937 Scott, Jr. Oct. 7, 1941 Clute 1 Sept. 12, 1944Armstrong Aug. 7, 1945 .Pifke Nov. 21, .1950

